Look at what graves Smokescreen does, reduced vision which is extremely powerful
Caitlyn's traps can has the potential to stay on the map indefinitely
Varus's Hail of Arrow, detonate his blight, applies healing reduction and slows while dealing all of that damage upfront
Jinx's Chompers can snare up to 3 people and have no cast time
Lucian's Ardent Blaze activates his passive and gives him movement speed as you attack marked enemies
Now look at "Make it Rain". It IS suppose to synergize with her ult. However there are no incentives to use it at all with its low 800 range and 1 second cast time!! At rank one its 90 magic damage over 3 second with a 25% slow.